204 TRANSACTIONS OF THE 



of July, August, and September, and a part of October, while the 

 numbers and activity of the larvae in ascending through and diffusing 

 themselves over the soil, was greatest toward the end of August. Any 

 measures to prevent the spread of the insect during the season should, 

 therefore, be taken prior to August, at least. 



It is also shown how readily the young insects will ascend through 

 the soil from superficial rootlets, and will attach themselves to any 

 object lying in their way, so that infection may be carried readily 

 from one vineyard to another by the mere passage of a wagon, plow, 

 or other implement, as well as through fruit boxes, prunings, and 

 cuttings. Especially are the eggs of the winged form liable to be thus 

 carried, even by gusts of wind taking up leaves, etc. The gall louse 

 form, now also recognized here, adds danger to this vehicle. 



Finally it is clearly shown that in ordinary soils no preventive 

 used only around the stock of the vine can offer security against the 

 ascent of either the winged or wingless form to the surface from out- 

 lying shallow rootlets, from which they can freely migrate to other 

 uninfected stocks; and that, therefore, the utmost care alone can 

 check the progress of the pest after it has once gained a footing. 



